#include <REGX52.H>

unsigned char LEDNum;
	
void Delay1ms(unsigned int xms)		//@12.000MHz
{
	unsigned char i, j;
  while(xms--) {
		i = 2;
		j = 239;
		do
		{
			while (--j);
		} while (--i);
	}	
}


void main() {
	P2=~0x01;
	while(1){
		if(P3_1==0){
			Delay1ms(20);
			while(P3_1==0);
			Delay1ms(20);
			
			LEDNum++;
			if(LEDNum>=8)
				LEDNum=0;
			P2=~(0x01<<LEDNum);
		}
		if(P3_0==0)
		{
			Delay1ms(20);
			while(P3_0==0);
			Delay1ms(20);
			
			if(LEDNum==0)
				LEDNum=7;
			else
				LEDNum--;
			P2=~(0x01<<LEDNum);
		}
	}
}


